PSI - Issue 78

Flavio Stochino et al. / Procedia Structural Integrity 78 (2026) 357–363

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Table 1 Mechanical properties of jute fiber nets.

Net Configuration Stiffness [N/mm] Strain Energy [kN·mm] Max Load [N] Max Displacement [mm] 2.5 × 2.5 cm 7.6 (C.o.V. 20.2%) 8.8 (C.o.V. 39.1%) 217.3 72.5 2.5 × 1.25 cm 10.3 (C.o.V. 11.9%) 14.1 (C.o.V. 21.0%) 337.2 82.9

The reference mortar was a cement-based M10 structural mix, with compressive strength ~10 MPa, shear strength ~0.15 MPa, and dry density ~1545 kg/m³. For the composite mortar, 1% by weight of 30 mm jute fibers was added to the mix, along with approximately 20% additional water (relative to total dry mass). This dosage was selected to optimize thermal insulation and strain energy without compromising workability. The walls were constructed using semi- solid hollow clay bricks (300 × 250 × 250 mm), compliant with Italian technical standards (D.M. 17/01/2018., n.d.). The bricks had a specific gravity between 800 – 860 kg/m³, and satisfied the seismic performance criteria: vertical compressive strength FBk ≥ 5 N/mm² and orthogonal strength f′Bk ≥ 1.5 N/mm². Retrofitting configurations included various combinations of nets, diatons, and composite mortar layers, a complete overview can be seen in Table 2. The test setup and material combinations were designed to evaluate the contribution of each component (nets, diatons, fiber-modified mortar) to the overall shear capacity improvement, with a focus on practical applicability and sustainability.

Fig 1. Loading set - up.

All the walls were tested with the set-up shown in Fig. 1. The applied quasi-static loading protocol involved an initial application of a constant vertical load, equal to approximately 2% (80 kN) or 1% (40 kN) of the wall's estimated maximum capacity. Subsequently, in-plane cyclic horizontal loads of increasing amplitude were applied through three horizontal hydraulic jacks. After the completion of the cyclic sequence, a monotonic horizontal load was applied until the wall reached its ultimate failure condition. In this paper, we focus exclusively on the evaluation of the ultimate load-bearing capacity. For a detailed discussion of the cyclic response and elastic behavior, the reader is referred to the full version of the study.